In the typical chemical toner process, such as an emulsion aggregation toner process, the resulting average toner particle size is of about 5.8 μm. Still, better image quality and lower toner coverage could be made possible by making toner particles with an even smaller average particle size. Nevertheless, with increasingly smaller toner particle sizes, it is more difficult to make a toner using current emulsion aggregation processes because of the relatively large particle size of the initial homogenized slurry particles.
In chemical emulsion aggregation processes, a mechanical homogenizer (such as a rotor-stator) is used to evenly disperse the coagulant into the toner slurry. Typically the homogenized slurry particle (pre-aggregated particle) size is about 3.3 μm at room temperatures (about 17-25° C.). Thus, to make a toner with a final average particle size of 3 or 4 μm is very difficult or impossible under the current processes. For example, to incorporate all the necessary components and still achieve a narrow geometric size distribution (GSD) while performing the necessary steps to make a toner, it would be very difficult when beginning with a 3 μm pre-aggregated particle.
As a result, there exists a need to develop a toner process with a smaller sized pre-aggregated particle that may subsequently be coalesced to achieve a much smaller particle sized final toner.